The invention relates to a rotor for a centrifuge, in particular for purifying lubricating oil in an internal combustion engine, wherein said rotor is rotatably mounted on a rotary axis in a centrifuge housing and provided with an impurity trapping element having an impurity collecting area and being delimited radially towards the outside by means of a circumferential wall, the rotor as a whole or its impurity trapping element being made of a plastic material and, on the interior of the impurity trapping element, a plurality of deflecting baffles being provided which are spaced apart from each other in circumferential direction and the rotor as a whole or its impurity trapping element able to be removed from the centrifuge housing for maintenance purposes.
Centrifuges and the rotors used therein for the purification of liquids, e.g. for the purification of lubricating oil in an internal combustion engine, have been widely used for decades and are accordingly known.
In the design of rotors for centrifuges, the objective is to accelerate the liquid entering the impurity trapping element as loss-free as possible to the angular velocity of the rotating rotor and, conversely, to return the spin energy of the liquid as far as possible to the rotor when the liquid flows out of the impurity trapping element. To this end, deflecting baffles are generally arranged in the impurity trapping element which extend radially or spirally and reduce the slip between the liquid and the rotor and thus improve the conditions for the separation of impurity particles—not only in terms of the achievable rotor speeds, but also with regard to the relative velocity of the liquid in relation to the impurity particles separated in the impurity trapping element. For rotors made of sheet metal, this function is usually realized by means of the embossments forming deflecting baffles on one front side or on both front sides of the rotor.
Taking into account a problem-free disposal of the separated impurity—this is essentially soot in the case of lubricating oil as the liquid to be cleaned—rotors and, respectively, impurity trapping elements made of a plastic material are increasingly used in new developments of centrifuges. Such rotors or impurity trapping elements provide the opportunity to thermally dispose of the filled rotor or, respectively, the filled impurity trapping element in a simple and relatively environmentally compatible manner.
One disadvantage in the use of rotors or impurity trapping elements made of a plastic material is that the strength of plastic materials is significantly below that of metallic materials. This disadvantage is especially evident when the rotor or the impurity trapping element must have an axially squat design with a large outside diameter—as is frequently necessary due to specified mounting space factors.
Another problem—especially in the filling stage of the rotor or the impurity trapping element during the run-up phase of the centrifuge—is that it cannot be excluded that individual chambers separated from each other by the deflecting baffles will be irregularly filled. This irregular filling of the chambers is connected with an unbalance and as a result thereof with reduced rotor speeds, vibration accelerations, and noise emissions.